Method and apparatus for setting well casing



April 4, 1944' c. A. YEATMAN 2,346,060

' METHOD AND APPARATUS FOR SETTING WELL CASINGS Filed March 18, 1941 2" sheets-Shet 1 April 4, 1944. C- A, YEATMAN Y22,;3-4'Z60 METHOD AND APPARATUS FOR SETTING WELL GASINGS Filed March 18, 1941 2 Sheets-Sheet 2 Patented Apr. 4, 1944 METHOD AND APPARATUS FOR SETTING WELL CASING Charles A. Yeatman, Los Angeles, Calif., assigner to Shell Development Company,

San Francisco,

Calif., a corporation of Delaware Application March 18, 1941, Serial No. 383,949

Claims.

The present invention relates to the art of drillingand completing wells, and pertains more particularly to methods and apparatus for landing or suspending a string of casing in a well and `performing the desired setting and cementlng operations.

As described, for example, in U. S. Patent 2,188,589, a well completion method in common use at present consists of first cementing the lower end of the casing string through the drilling riser and then, after the cement has hardened, placing the casing string under a predetermined tension, cutting the top casing Joint to a required length and flanglng or fastening it to the casing or landing head by means of a special coupling. This method requires many relatively intricate axial alignment oi. the casing string with the casing head. Likewise, the hoisting equipment is im- .'rnobilized for several days while the cement is hardening. Another disadvantage of this method lis that heavier pipe is necessitated when an extra .tting manipulations, for example, to accomplish small vent ports and lines in the landing head so that a suicient uid circulation cannot be ob- :1.

tained thereby. If, to overcome the latter, the

' vent ports are enlarged, the strength of the landing head is considerably decreased.

It is therefore an object of this invention to provide a method for setting a string of casing in a wellwherein said string is first landed or iianged at the casing head,.and is then cemented at the level of its lower end.

It is also an object of this invention to provide a methodfor setting casing wherein said casing is run into the well and landed or flanged at the head without subsequent adjustment of tension.

It is also an object of this invention to provide a method of landing or suspending a string of casing from a casing head without interrupting iiuid communication through the annular -space surrounding said 4casing below and above said point of suspension.

Itis also an object of this invention to-provide a casing head structure whereby casing may be lowered into the borehole through the casing head while controlling the pressures within said casing and within the annular space surrounding said casing.

It is also an object of this invention to provide an improved well head structure to carry out the process of this invention.

It isstill another object to provide a superior casing support in which the annular space around -the inner casing being supported remains open for uid iiow until closure is desired, and means are provided for effecting said closure when desired.

It is a lfurther object to provide an improved casing support of compact design which is inexpensive and requires simple manipulations to install.

It is another object to provide a compact well head structure comprising a tubing head in which is embodied the casing vent outlet or outlets.

With the above and other objects in view the invention has particular relation to certain novel features of construction, operation and arrangement of parts, an example of which is given in this speciiication and illustrated by the accompanying drawings, wherein:

Figure I is a vertical sectional view, showing the general arrangement of apparatus used in landing casing and circulating in cement according to the present invention;

Figure 1I is a vertical sectional view of a well head structure, showing two inner casing strings landed according to the present invention;

Figure III is a vertical sectional yiew of the completed casing head structure:

Figure IV is a plan view taken along the lines IV-IV of Figure III, with the tubing head, sealing ring and packing rings removed;4

Figure V is a vertical sectional view of the segmented bushing detail;

Figure VI is a. plan view of said segmented bushing.

Brieiiy, the method of the present invention comprises the steps of landing or suspending a. casing string on a casing -or landing head, circulating fluid from above the point of suspension down through said string and up through the annular space outside said casing and on through the casing head out of the well, and cementing the lower end of the casing string.

'I'he equipment used according to the present invention in setting or landing an inner or intermediate casing string I 9 in a borehole I8 is shown generally in Figures I and II oi the drawings.

An outer or surface casing string 5 is shown as already cemented in the borehole and is provided at the top with a casing head. generally designated as I, which rests on a concrete or other suitable foundation, such as on the bottom of a concrete cellar, being provided for this purpose lwith a wide diameter landing base I and supporting radial webs I I, as shown in Figures I and III. As shown in more detail in Figures III and IV, the casing head I, as well as any head which may be used to support further casing strings within the outer string 5, is formed with a tapered shoulder 3 protruding into the upper portion of the bore 6 of the casing head and forming therein a tapered seat. The lower portion of the bore 4 of the bottom head may be threaded to engage the outer surface casing 5, although any other suitable means for supporting the surface casing, such as welding, may be used instead. A horizontal vent port I4 and valved line I5 connected thereto may be provided in the body portion of the casing head I for use in subsequent testing and sampling. The casing or landing head I is formed with an upper flange 1, which may have circular grooves 8 adapted to receive packing rings 9, as shown in Figure III, and which may also have circumferentially spaced bores 6, serving as means for connecting to a drilling riser, smaller casing heads, tubing heads, etc, as desired.

The upper end of the casing string I9, which is to be landed or hung in the bottom casing head,

tion with the casing string I9 and threaded at l the upper end for a subsequently-described .purpose. The body of the coupling is provided with radial ribs orybushing segments 2I projecting outside from the coupling body. Thelower portion of the rib 2I is tapered at substantially the same angle as the tapered shoulder 3 of the casing head and is adapted to seat on said shoulder 3, as shown in Figure III. The upper face 22 of each of ribs 2I is horizontal and the ribs 2I are so formed that these faces 22 are a short distance below the upper end of the coupling 20. When the coupling 20 and the casing string I9 attached thereto is seated in place on the tapered shoulder 3, the coaction of the upper rib faces 22, the upper end oi' the body of the coupling 20 and the upper end of the bore of the casing head I together forms a groove 25, as shown in Figure III. Fluid can pass upward (as well as in the reverse direction) from the annular space between the outer casing 5 and the inner casing string I9 through the spaces or channels between the ribs 2I and through the groove 25. As hereinbelow described, after the lower end of the casting string I9 is cemented, -a seal-ing ring 26 is placed in the groove 25 and preferably welded or otherwise attached thereto, whereby the above-mentioned fluid passage is closed. The sealing ring 26 is preferably formed with a circular groove 21 in its upper face, as shown most clearly in Figure III, whereby the ring may be easily welded into place.

In a like manner, as shown in Figure II, further casing heads 62 of similar construction but smaller size may be surmounted on the above-described base casing head for supporting and hanging further casing strings 6I within the outer casing string 5.

Surmounting the uppermost casing head, such as the base or bottom head I (when only one casing string besides the surface casing is used),

as shown in Figure IIL-is a tubing head, generally designated as 4B, for suspending lthe tubing string 4I in the well. The tubing head 40 is preferably a anged body having circumferentially spaced bores for connecting by means of bolts I3 to the upper angel of the casing head I or the like and having an axial bore. suitably formed, such as with threads, for attachment to the upper end of the tubing string II. The lower end of the axial bore is.counterbored as at 46 to a diameter about that ofthe bore of the casing head to which the tubing head 45 is attached. A horizontal vent bore 4T, which may be formed with a threaded extension 49, is provided in the tubing head 40 and opens into the counterbore 46. Suitable attachment means, such as upwardly-projecting stud bolts 6I), are provided'in the upper horizontal face of the tubing head for fastening thereabove a "Xmas tree and other control equipment, as shown at 59 in Figure II.

In carrying out .the method of the present invention, which for purposes of illustration will be described in relation to thev above-described preferred apparatus, shown in Figure I, the surface casing 5 and the bottom casing head I having tapered seat 3 are installed in the usual manner well known to the art. After the borehole has been drilled to the desired depth for settingl duction of the casing string 5 while maintaining l the well under pressure control, and the mud line 52 allows circulation of drilling fluid, as is well known in the art. Before lowering the last section of casing I9 into the drilling riser 50, the special coupling 20 is threadably or otherwise attached to the upper end of the casing string I9. and a lifting nipple 55 is attached to the upper end of the coupling. The casing string I9 and coupling 20 are then lowered into the drilling riser and borehole by means of the lifting nipple until the tapered radial ribs 2| seat upon the tapered annular shoulder 3 of the casinghead I.

With the well thus under pressure control and the casing string I9 landed and the blow-out preventer 5I open, drilling mud, water, oil or any other suitable uid is circulated (as indicated by the arrows in Figure I) down through the lifting nipple or pipe 55 and casing string I9 and' up through the annular 'space between the casing string I9 and the walls o1' the borehole I8 or l outer casing string 5 and through the space between the supporting ribs'2`I and on through the annular space between the landing nipple 55 and the drilling riser and on out the 'mud line T 52 to a disposal or recovery pit or the like. The circulation of fluid washes the borehole 4walls free from adhering mud iluld in order that cement ywill be able to form a good bond with the walls.

After the borehole1 is suiilciently cleaned, a cement slurry is forced down through the pipe 55 into place behind the llower end of the casing string in any suitable manner, such as by means of spacer plugs and an overload of mud iluid, oil or the like, while the overflow of liquid displaced from the annular space between the casing string and borehole walls passes freely out of the well through mud line T 52.

While the cement is hardening, the lifting nipple 55 may be disconnected from the coupling 20, the drilling riser 50 removed, and ,annular packing ring 26 suitably sealed into the groove 25, closing the uid passage between the radial ribs 2 I If the well is deepened by continued drilling, additional casing heads are surmounted on the bottom casing head as they are needed for suspending the additional casing strings, as shown in Figure II. For each casing string the above-described method of landing the casing in the casing head, circulating the wash liquid and cementlng in the lower end or suitable portions of the casing string is applied.

With the desired casing strings installed, a tubing string Il may be suspended in the Well from a tubing head, such as the preferred form Il hereinabove described. With the tubing head l5 in placeand the tubing string 40 attached thereto, the desired control4 equipment, such as blow-out preventer, gate and flow valves, etc.,

, commonly known as the Xmas tree 59, may be surmounted `on the tubing head 40 by means of the stud bolts 50. y

Although the method of the presenty invention has been described in relation to the illustrated preferred form of apparatus, it will be readily understood that the present invention is not limited to the apparatus described but refers broadly to the method of landing a single casing 'string or a casing string within an outer casing string, controlling well pressures within said string and within the annular space around said string, circulating a fluid through said string and said annular space past the point of suspension of said string, and cementing said string.

I claim as my invention:

l. The combination of a casing head having an axial bore constricted by a tapered annular shoulder, a casingA coupling having spaced radial outwardly projecting ribs, each of said ribs having an upper horizontal face spaced a short distance below the upper end of said coupling and a lower vinwardly tapering face adapted to seat on said shoulder, and means for closing the passages formed between saidv spaced ribs, said means comprising an annular sealing member insertable between the Walls of said axial bore and said coupling above said ribs, said sealing member being adapted to be permanently secured to said walls A and said coupling.

2. The combination of a casing head having an axial bore constricted by a tapered annular shoulder, a casing coupling having spaced radial outwardly projecting ribs, each of said ribs hav'- `ing an upper horizontal face spaced a short distance below the upper end of said coupling and a lower inwardly tapering face adapted to seat on said shoulder, and means for closing the passages formed between said spaced ribs, said means comprising an annular sealing member insertable between the walls of said axial bore and said coupling above said ribs, said sealing member being adapted to be permanently secured tti said walls and said coupling, said annular member having on its upward face a circular groove.

, 3. In a well head structure, the combination of a casing head having an axial bore provided with an annular constriction, an outer casing stringattached to said casing head at the lower portion of said bore, an inner casing string, a couplingrigidly attached to the upper end of said inner casing string, said coupling having spaced radial outward projections adapted to seat on said annular constriction, a tubing head surmounted o`n and attached to said casing head, said tubing head having an axial bore, a tubing string attached to the upper portion of said tubing head in .said bore, the lower portion of said bore being counterbored to a greater diameter than the upper portion, and a transverse bore in said tubing head leading from said counterbored portion of the tubing head to the outside, said transverse bore forming a vent outlet from the space between the tubing string and the inner casing string.

4. In the process of landing cn a casing head a casing string having an outwardly enlarged axially channeled portion, the steps of lowering said string into the borehole until said enlarged portion engages the inngnwalls of the casing head, thereby suspending said string from the* casing head, lowering a charge of cement into the borehole through said string and forcing it :behind said string by controlling from a point above the casing head the pressure within said string and the pressure in the annular space between said string and the Walls of the borehole, said last control being effected through the channels in said enlarged portion of the string.

5. In the process of landing on a casing head supporting a shorter outer casing string a longer inner casing string having an outwardly enlarged axially channeled portion, the steps of lowering said inner string into the borehole within said outer string until said enlarged portion engages the inner walls of the casing head, thereby suspending said inner string from saidv casing head, circulating in the borehole a iiuid by passing it in one direction through said inner string and in the other direction through the annular space between the outer and the inner strings and .applying uid pressure from the top, and permanently securing said inner string to the casing i head, thereby closing said channels.

CHARLES A. YEATMAN. 

